Retarding mechanism for lifting-jacks



- w. E. LOMBARD. RETARDING MECHANISM FOR'LIFTING JACKS. APPLICATION FILED AUG-3,1920. 1,383,221 Patented June 28, 1921.

3 SHEETS-SHEET i- I 6 nmimi 7 Mentor: mr w W. E. LOMBARD.

RETARDING MECHANISM FOR LIFTING JAC'KS. APPLICATION HLEu AUG.3. 1920.

Patented June 28, 1921.

. 3 SHEETS-SHEET 2.

W. E. LOMBARD. RETARDING MECHANISM FOR LIFTING JACKS. APPLICATION FILED AUG-3, 1920.-

3 SHEETS-SHEET 3- Patented June 28, 1921.

UNITED STATES PATENT OFFICE.

WALTER E. LOMBARD, or 'ABLENGTON, ranssnenusnrrs, ASSIGNOR TO A. o. NORTON Inc, or BOSTON, 1VI1-LSSAGI-IUSETTS, A CORPORATION or MAINE.

BETARDIITG MECHANISM FOR LIFTING-JAGKS.

Specification of Letters Patent. Patented J n 28 1921 Application filed August 3, 1920. Serial No. 401,069.

To all to [tom it may concern Be it known that I, \VAL'rnR E. LOMBARD, a citizen of the United States of America, and a resident of Arlington, in the county of Middlesex and State of Massachusetts, have invented certain new and useful Improvements in Retarding Mechanism for Lifting-Jacks, of which the following is a specification.

This invention relates to retarding mechanism for high speed lifting jacks and has for its object the provision of means for preventing the jack lowering too rapidly.

The invention consists of providing the worm shaft of a self-run-do'wn lifting jack with a speed retarder connected thereto by a one-way driving connection whereby said retarder is rotated in one direction only and that duringthelowering of the jack.

The invention further consists in mechanism whereby the brake arms may be sepa rated from the retarding device to permit the lowering of the load, said mechanism including means whereby the speed may be controlled manually and means whereby the retarding device may be placed out of commission to permit the jack to be lowered by hand.

The invention further consists in certain novel features of construction and arrangement of parts which will be understood readily by reference to the description of the drawings and to the claims to be hereinafter given.

For the purpose of illustrating theinvention, one preferred form thereof is illus trated in the drawings,this form having been found to give satisfactory and reliable results although it is to be understood that the various instrumentalities of which the invention consists can be variously arranged and organized and the invention is not lim itedto the precise arrangement and organization of these mstrumentahties as herein shown and described, except as required by the scope of the appended claims.

iOf the drawings:

Figure 1 represents a vertical sectionof a lifting jack embodying the principles of the present invention.

Fig. 2 represents an elevation of the removable plate carrying the operating mechanism, the operating shaft being shown in section.

Fig. 3 represents an elevation partly in section, of the brake wheel and devices coacting therewith.

Fig. 4 represents a horizontal section on Similar characters indicate like parts throughout the several figures of the drawings. i 11 the drawings, 10 represents a suitable base supporting a stationary standard 11.

over the outer periphery of which is fitted a movable sleeve 12, to the upper end of which is threaded a cap 13. f

In the upper end of the standard 11.is

mounted anut 1 to whichisthreaded a.

lifting screw 15 having splined to its upper reduced end a bevel gear 16 with which meshes a bevel gear 17 formed upon or secured to a revoluble shaft or spindle"18, the outer end of which is provided with a suitable operating mechanism 19 of i any well-known construction.

Between the upper face of thebevel gear 16 and the inner face of the cap 13 are two annular plates 20, 21, between which are in-;

terposed a plurality of anti-friction members 22. v

The movablemember 12 ,isprovided on one side with a flanged projection 24: having a removable plate 25 secured thereto by.--

bolts 25*. V p p The plate 25 is providedwith abearing 26 for the spindle or shaft 18 and secured to the shaft 18 is a gear 29.

Beneath the gear. wheel 29 is arevolubleshaft 35 having secured thereto: a.pinion 36 meshing with said gear 29 and. driven thereby when the movable member 12 of the .jack moved in either direction.

The shaft 35 has also secured thereto as On the reducedMendA-l or the. worm 38 shown in the drawings.

Mounted in the bracket 40 and. alined with the worm 38 is an oscillating shaft 51 having secured to its outer end an actuator 52 and at its inner end a cam disk 53 havlng in the periphery thereof a depression 54 in which said projection is adapted to be positioned under normal conditions.

The depressions 54 are sufficiently deep to permit the brake members 43 to be forced intocontact with the brake wheel 42 which is loosely mountedon the reduced end 41 of the Worm 38.

In other words, the projections 50 are not in contact normally with the cam disk 53 as shown in Fig. 3.

When, however, the cam disk 53 is moved in the direction of arrow at on Fig. 3, the gradually inclined cam throw 55 will come into contact with the projections 50 and move'thebrake members 43 against the tension of the springs from contact with the brake wheel 42.

Owing to the inclination of said cam throws 55, the movement ofthese members 43 from the brake disk42 may be varied at 'W hen it' is desired to lower the jack by hand, the cam disk 53 is moved in the opposite directionto that indicated by the arrow a on Fig. 3 and the cam throw 56 will move the projections 50 outwardly until they rest upon the peripheral surface 57 which is a greater distance from the axis of the oscillating shaft than the peripheral surface 57 x at the outer end of the cam throws 55.

.Each brake arm 43 is provided on its inner facefwith a'curved spring member 58 se-' cured thereto with its free end resting in a' depression 59 said members 58 thereby forming bridges which with the inner curved faces of the members 43 form a continuous surface with which coact the pivoted shoes 60 on the brake wheel 42.

When the brake wheel 42is moved in the" direction of the arrow Z) on Fig. 6 of the drawings, thebrake shoes 60 will move outwardly. about their pivots 61 and create suflicient friction on the brake members 43 and bridges 58 to retard the speed of rotation of the worm 38 and consequently regulate the'lowering of the movable member 12' of the jack.

Each shoe 60 has a projection 62 adapted curs however when it is desired to operate" the jack without permitting it to lower under its load.

Secured to and 'revoluble with the reduced end 64 of the worm 38 is a disk 65 having mounted thereon a plurality of pawls 66 pivoted at 67 and adapted when the disk 65 is rotated in the direction of the arrow 6 on Fig. 6 of the drawings to engage with the teeth of the ratchet wheel 68 keyed to and revoluble with the hub of the brake wheel 42, loosely mounted upon the reduced end 41 of the worm 38.

The worm 38 is rotatable in either direction when the load is being lifted or when cess in the brake wheel 42 as shownin Fig.

4 of the drawings. V

When the jack is being raised, the pawls 66 will ride over the teeth of the ratchet 68 and impart no movement to the brake wheel 42 but when it is desired to lower the load under its own weight, the disk 65 will be moved in theopposite direction and the pawls66 becoming engaged with the teeth [of the ratchet 68 will cause the brake wheel '42 to be rotated therewith whenever the brake members 43 are moved by. the cam disk 53 from contact with the brake wheel 42.

As the worm 38 rotates and causes the V rotation of the brake wheel 42, the shoes 60 inner surfaces of the brake arms 43 and the bridges 58 and retard the speed so that any excessive speed of lowering will be prevented.

The degree of retarding may be varied by manipulating the actuator 52.

To retain the load in elevated position the cam disk 53' is in the position indicated in Fig. 3 ofthe drawings and atthis' time the brake members 43 will grip upon the brake wheel 42 sufliciently to prevent itsrotation and owing to the engagement of the pawls 66 with the ratchet wheel 68 keyedto said brake V wheel the disk 65 will also be prevented from rotating. it v f Owing to this disk 65 being locked from rotation, the worm 38 cannot be rotated and therefore there can be no lowering of the load untilthe brake members 43 are moved from contact with the brake wheel 42.

This makes a simple and effective device having a worm shaft adapted to be driven in either direction; a brake wheel loosely mounted on said worm'shaft; a member revoluble with said worm shaft; a one-way driving connection between said brake wheel and said'member and a braking member adapted to coact with said wheel.

2. The combination with a lifting'jack having a worm shaft-adapted to be driven in either direction; a brake wheel loosely mounted on said worm shaft; a member revoluble with said worm shaft; a one-way driving connection between said brake wheel and said member; a braking member adapted to coact with said wheel and a cam member alined with said worm shaft for separating said braking member from the brake wheel.

3. The combination with a lifting jack having a worm shaft adapted to be driven in either direction; a brake wheel loosely mounted on said worm shaft; a member revoluble with said worm shaft; a one-way driving connection between said brake wheel and said member; a braking member adapted to coact with said wheel; and a cam member alined with said worm shaft for separating said braking member from the brake wheel, said cam wheel being provided with two cam throws one of which is adapted to move the braking member a short distance while the other is adapted to move said braking member a much longer distance.

4. The combination with a lifting jack having a worm shaft adapted to be driven in either direction; a brake wheel loosely mounted on said worm shaft; a member revoluble with said worm shaft; a one-way driving connection between said brake wheel and said member; a braking member adapted to coactwith said wheel; a stud projecting from said braking member; and a cam member alined with said worm shaft and provided with a gradually inclined throw adapted to coact with said stud when rotated in one direction.

5. The combination with a lifting jack having a worm shaft adapted to be driven throw adapted to coact with said stud when movedin the opposite'direction. 7

6. The combination of a Tworm shaft adapted to be driven in either direction; a brake wheel loosely mounted on said worm shaft; a member revoluble with said worm shaft; a one-way driving connection between said brake wheel and said member; a bra];- ing member adapted to coact with sald -wheel; a stud projecting from said braking member; a cam member alined with said worm shaft and provided with a gradually inclined throw adapted to coact with said stud when rotated in one direction; .anda

steeply inclined throwadapted to coact with said stud when moved in the opposite direction; said steeply inclined throw terminating in a portion concentric. to the axis of the worm shaft and at agreater distancefrom 'said axis than the outer end of said gradually inclined throw.

.7. The combination with a lifting jack having a worm shaft adapted to be driven in either direction; a brake wheel loosely mounted on said worm shaft; means on said worm shaft adapted to rotate said brake wheel in one direction only and that during the lowering of the load; a braking member .normally coacting with said. wheel; and

means for moving said braking member from contact with said wheel.

8. The combination with a lifting jack having a worm shaft adapted to be driven in either direction; a brake wheel loosely mounted on said worm shaft; means on said worm shaft adapted to rotate said brake wheel in one direction only and that during the lowering of the load; a pivoted braking member normally coacting with said wheel; and means for moving said braking member about its pivot from contact with said wheel.

9. The combination with a lifting jack having a worm shaft adapted to be driven in either direction; a brake wheel loosely mounted on said worm shaft; means on said worm shaft adapted to rotate said brake wheel in one direction only and that during the lowering of the load; a braking member normally coacting with said wheel; and cam mechanism for moving said braking member from contact with said wheel. 7

10. The combination with a lifting jack having a worm shaft adapted to be driven in either direction; a brake wheel loosely mounted on said worm shaft; means on said worm shaft adapted to rotate said brake wheel in one direction only and that during the lowering of the load; a braking member normally coacting with said wheel; and an oscillating member adapted when moved in one direction to move said braking member gradually from said wheel and when moved in the opposite direction to move said braking member a greater distance from said wheel.

11. The combination with a lifting jack having a worm shaft adapted to be driven in eitherdire'ction; a brake wheel loosely mounted on said worm shaft; means on said worm shaft adapted to rotate said brake 'wheel in onedirectiononly and that during the lowering of the load; abraking member normally coacting with said wheel; and an ing -member a; greater distance from said 'Wheel and retain it in its separated position.

oscillating member adapted when moved in one direction to move said braking member gradually from said wheel and whenmoved in "the'opposite direction to move said-brak- 12. "The combination with a lifting jack a WOrmTShaft adapted to bedriven in either direction; a brake wheel loosely mounted' on said worm shaft; a ratchet secured thereto; a disk revoluble with said Worm shaft;-pawls carried by saiddisk and coacting with said ratchet; abraking'member normally contacting with said wheel;

and means for separating said'brakingmemberfrom said wheel.

13. The combination With a liftingjack having a-worm shaft adapted to be driven in either direction; a speed-retarding device loosely mounted on said worm shaft; and means on said wormf sha'ft forrotatin-gsaid retarding device in'one direction only and "that du'ring the lowering of the load.

14. The combination with a liftingjack having a worm shaft adapted tobedriven in either direction; a speed retarding device loosely mounted on said worrnshaft and in- 15. The combination with 'a'lifting jack having a worm shaft-adapted to be driven loosely mounted on said worm shaftand ineluding a plurality of peripheralshoes' movable outwardly :dnring therotation of said retarding device; means on said worm shaft in either direction; a speed retarding device 5 forrotating-said retardingdevice in one di-' rection-only and that during the lowering of the load and braking members normally coactlng wlth sald retarding device and adapted to be removed from contact therewith' topermit said shoesto move outwardly into frictional contact a with 7 said braking members.= i

i WALT-nan; LoMBARD. V 

